If you are suffering from horizontal banding or if one or more colours are not coming out, then these print head cleaning cartridges are designed to clear your blocked nozzles. Simply insert the cleaning cartridges into your machine and print as normal. Instead of ink passing through the nozzles, cleaning solution will be fed through the printer and onto the paper. We recommend you print full pages of colourful pictures so that plenty of the cleaning solution is distributed through the printer. For example, if there is a problem with the Cyan colour then print pictures of a sky. This will concentrate the cleaning solution in the correct area.